Recently, a contactless information medium including an IC chip and an antenna has been widely used in various fields, such as distribution, traffic, finance, entertainment, and amusement. For example, a currently-used contactless information medium includes a body, an IC chip, and a coil antenna. The body forms a profile of the contactless information medium. The IC chip is housed in the body. The coil antenna is formed of a string of conductive wire, both ends of the conductive wire being connected to the IC chip. The coil antenna includes a main arrangement pattern provided along a closed curve and a plurality of sub-arrangement patterns each having a smaller diameter than the main arrangement pattern. The contactless information medium further includes a plurality of bobbins provided in the body and arranged along the closed curve. The string of conductive wire is wound around the plurality of bobbins along the closed curve to form the main arrangement pattern, and the string of conductive wire is wound around each of the bobbins to form the sub-arrangement patterns. See, International Publication No. WO2013/099546. This enables communication between each of a plurality of contactless information media and a communication device while the contactless information media are stacked.